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Guidance · 11 min read
Reporting a road traffic collision to UK police: when, how and what reference numbers to keep
When you must report a UK collision to the police under section 170 Road Traffic Act 1988, the difference between 999, 101 and online collision reporting, and which reference numbers your insurer will need.
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Reporting a road traffic collision to UK police: when, how and what reference numbers to keep
Knowing exactly when a UK road traffic collision must be reported to the police, and through which channel, saves a non-fault driver from two very common claims problems: a delayed insurer notification and a missing reference number that the third-party insurer's claims handler then uses to challenge the account of events. This post sets out the statutory duty under section 170 of the Road Traffic Act 1988, the practical 999, 101 and online channels each force operates, and how to capture the reference numbers your insurer and accident management partner will need.
The section 170 duty in plain terms
Section 170 of the Road Traffic Act 1988 imposes two separate duties. First, the duty under section 170(2) and (3) is to stop at the scene, give particulars when reasonably required, and produce a certificate of insurance where someone has been injured. Second, the duty under section 170(6) is to report the accident at a police station as soon as reasonably practicable and in any event within 24 hours, where the section 170(2) particulars could not be exchanged at the scene.
The duty applies where the accident causes (a) injury to anyone other than the driver of the relevant vehicle, (b) damage to another vehicle, (c) damage to an animal not in the vehicle (specifically horses, cattle, asses, mules, sheep, pigs, goats and dogs), or (d) damage to property on or adjacent to the road. Failure to stop or to report is a criminal offence under section 170(4); penalties include unlimited fines, six to ten penalty points and discretionary disqualification.
DETAIL
03
Section 3 of the walkthrough.
When to call 999
Call 999 if anyone is injured or you cannot tell whether anyone is injured. Call 999 if a vehicle is blocking a live carriageway, particularly on a motorway or smart motorway. Call 999 if a driver fails to stop. Call 999 if you suspect drink or drug driving. Call 999 if you suspect the other driver is uninsured, has used false details, has stolen the vehicle, or is otherwise committing a crime.
The 999 call generates a Computer Aided Dispatch (CAD) reference. This reference is the master record of the call and your reporting time, and your insurer's claims handler will quote it in correspondence. Note the CAD reference at the scene if it is given verbally; otherwise call 101 the same day and ask the call handler for the reference associated with the earlier 999 call.
When to call 101
Call 101 (or use the equivalent non-emergency number) for non-injury collisions where you could not exchange details at the scene, where you want a record made, or where there is no immediate threat to life. The 101 service is operated by each force individually and the call handler will record the report; the reference issued is typically a CRIS (Crime Report Information System) reference where any criminal element is involved, or a non-crime collision reference otherwise.
In England, Wales and Scotland, 101 connects to the local force on the basis of where you are calling from. If you have moved by the time you call, ask to be transferred to the force area where the collision occurred. Most forces also accept reports through an online reporting form, which is faster and produces a written reference.
The Met Police MPS Collision Reporting Service
In Greater London, non-injury collisions involving the Metropolitan Police are reported through the MPS Collision Reporting Service online tool. It walks through the standard questions - date, time, location, vehicle details, what happened - and produces a unique reference that is emailed to the reporter. The City of London (the Square Mile) is not policed by the Met; the City of London Police operate their own collision reporting process accessed through the City of London Police website.
The online tool is the Met's preferred reporting channel for non-injury cases and reflects the way most reportable accidents are now logged. The reference issued is the one to quote in correspondence. The Met will only normally send an officer to the scene where injury is reported, where there is suspected drink or drug driving, where a driver has failed to stop, or where the road is blocked.
06DETAILKey takeaway
When the police actually attend
Where police attend, the officer typically takes a contemporaneous note from each driver, photographs the scene, may breath-test drivers, and collates witness details. A copy of any collision investigation report (the form numbers vary by force but the underlying documents are sometimes called MG-NFA or the local equivalent) is held by the force and disclosed on request, often through a paid request process.
The CAD reference and any subsequent CRIS reference issued by the attending officer are the references your insurer needs. Police attendance does not by itself decide liability; insurers reach a liability decision on the totality of the evidence including, but not relying solely on, what the police observed at the scene.
What if the other driver does not stop or refuses to give details
The first step is to record everything you can - registration if visible, make, model, colour, direction of travel, time, location, and any partial plate or company name. Call 999 if anyone is injured or the driver is being driven dangerously; otherwise call 101 or report online within 24 hours under section 170(6).
Where the at-fault driver remains untraced, the claim can be routed through the Motor Insurers' Bureau Untraced Drivers' Agreement 2017. Where the at-fault driver is traced but turns out to be uninsured, the claim is routed through the MIB Uninsured Drivers' Agreement 2017. Both processes need the police reference number, so reporting promptly is essential.
Reference numbers - what to keep, what to quote
Keep all three reference families: the CAD reference (from the original 999 call), the CRIS reference (where one is issued), and the online collision reporting reference. Quote the most specific reference in any subsequent correspondence with the third-party insurer. Where you have multiple references, list them all in the first letter so the insurer's claims handler can match the file regardless of which reference they have on their system.
Where the driver of the at-fault vehicle was a professional driver - a bus driver, taxi driver, courier, HGV driver - record the operator name, vehicle number, driver badge number where visible, and any company markings on the vehicle. The operator's own incident report will exist independently of the police record and is a separate disclosure stream.
DETAIL
09
Section 9 of the walkthrough.
Time limits - the 24-hour rule and what 'as soon as reasonably practicable' means
Section 170(6) requires a reportable accident to be reported as soon as reasonably practicable, and in any event within 24 hours. 'As soon as reasonably practicable' is interpreted strictly: you cannot wait 23 hours and 59 minutes if you could practically have reported earlier. In practice, calling 101 or using the online tool the same day satisfies the duty.
Where you are physically unable to report - for example because you are in hospital - the duty arises as soon as you are practically able. A friend or family member can report on your behalf with your authority. Late reporting does not by itself defeat a non-fault claim, but it gives the third-party insurer an avenue to challenge the timeline and is best avoided.
Take action
If you have just been in a non-fault collision, the fastest way to protect your claim is to open the file with us inside the first hour. We dispatch recovery, lodge the relevant CCTV requests inside the retention window, and notify the third-party insurer for you.
We do not provide legal advice. This article is general guidance for UK drivers. Personal injury enquiries are referred only with your consent to authorised legal or regulated partners. Specific limits, retention windows and process steps may change; the position at the date of any individual collision will govern the handling of that claim.
Frequently asked questions
- Do I have to report a minor scrape with no injuries to the police?
- Only if you could not exchange section 170(2) details at the scene. If both drivers exchanged full details, no police report is required, although your insurer may still want a record.
- What is a CAD reference?
- A Computer Aided Dispatch reference, generated automatically by the call-handling system when you call 999 or 101. It identifies the call and the time the report was made.
- Will the police give me a copy of their report?
- Most forces release a STATS19 collision report or local equivalent on request, sometimes for a fee. Where criminal proceedings are pending, disclosure is delayed until they conclude.
- Can I report online instead of calling?
- In most force areas, yes - online reporting is now the default for non-injury collisions. The Met Police MPS Collision Reporting Service in London is the canonical example.
- What if the other driver said they would call but didn't?
- Report it yourself within 24 hours. The duty is on each driver individually; you are not relieved by the other driver's promise.
- Do I need to report a hit-and-run?
- Yes. Call 999 if anyone is injured, otherwise 101 or online within 24 hours. The reference is needed for any subsequent claim through the Motor Insurers' Bureau Untraced Drivers' Agreement.
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